Eclogite Facies Regional Metamorphism of Hydrous Mafic Rocks in the Central Alpine Adula Nappe

The Adula Nappe is a slice of Pre-Mesozoic continental basement affected by Early Alpine (Mesozoic or Lower Tertiary) high-pressure metamorphism. Mineral compositions in mafic rocks containing omphacite + garnet + quartz record a continuous regional trend of increasing recrystalliza tion temperatures and pressures that can be ascribed to this regional high-pressure metamorphic event. P-T estimates derived from mineral compositions grade from about 12 kb and 500 °C or less in the north of the nappe to more than 20 kb/800 °C in the south. The regional P-T trend is associated with a mineralogical transition from assemblages containing additional albite and abundant amphiboles, epidote minerals, and white micas in the north (omphacite-garnet amphibolites) to kyanite eclogites containing smaller amounts of hornblende and zoi.site in the south. Textures and mineral compositional data show that these hydrous and anhydrous silicates associated with omphacite + garnet + quartz arc primary parts of the high-pressure assem blages. Observed phase relations between these primary silicates, theoretical Schreinemakers analysis, and the thermobarometric results, together indicate that the regional transition from omphacite amphibolites to kyanite eclogites can be described by two simplified reactions: alb+epi+hbl=omp+kya+qtz+par (H2O-conserving) (15) par+epi+hbl+qtz=omp+kya+H2O (dehydration) (12) which have the character of isograd reactions. Local variations of water activity (aH2O) as indicated by isofacial mineral assemblages, and the H2O character of the reaction (15), are interpreted to reflect largely H and predominantly fluid-absent high-pressure metamorphism within the northern part of the nappe. The omphacite amphibolites and paragonite eclogites in this area are thought to have formed by H2O reactions from Pre-Mesozoic high-grade amphibolites, i.e. from protoliths of similar bulk H2O-countent. The second ‘isograd' (12) is interpreted to mark the regional transition from largely fluid-absent metamorphism in the north to fluid-present metamorphism in the south, where metamorphic pressures and temperatures in excess of 12-15kb and 500-600°C were sufficient for prograde in-situ dehydration of similar hydrous protoliths to kyanite eclogites. The observation of abundant veins, filled with quartz+kyanite+omphacite, suggests that a free fluid coexisted locally with the kyanite eclogites of the southern Adula Nappe at some time during progressive dehydratio

Simultaneous cathodoluminescence hyperspectral imaging and X-ray microanalysis

A facility has been developed to acquire hyperspectral cathodoluminescence (CL) images simultaneously with X-ray composition data. Based around an electron microprobe, the system uses a built-in Cassegrain microscope to efficiently couple emitted light directly into the entrance slit of an optical spectrograph. A cooled array detector allows the parallel acquisition of CL spectra, which are then built up into a multidimensional data-cube containing the full set of spectrally- and spatially-resolved information for later analysis. This setup has the advantage of allowing wavelength-dispersive X-ray (WDX) data to be recorded concurrently, providing a powerful technique for the direct comparison of luminescent and compositional properties of materials. The combination of beam and sample scanning thus allows the correlation of composition and luminescence inhomogeneities on length scales ranging from a few cm to sub-micron

Copper partitioning between silicate melts and amphibole: Experimental insight into magma evolution leading to porphyry copper ore formation

AbstractA series of piston cylinder experiments were conducted to determine the partition coefficient of Cu between amphibole and andesitic to rhyolitic silicate melts. The experiments were run at T=740–990°C, P=0.7GPa, oxygen fugacity (fO2) ranging from that of the Ni-NiO buffer (NNO) to 2.3 log units higher (NNO+2.3 and dissolved water in variable concentrations (under-saturated to saturated conditions). Fixed metal activities were imposed by using Au97Cu3 and Au92Cu8 alloy capsules, which allowed simultaneously determination of Cu solubility. Our data demonstrate that Cu solubilities in both the silicate melt and amphibole decrease with decreasing temperature. The solubility of Cu decreases by a factor of 6 from 990 to 740°C in equilibrium with andesitic to rhyolitic melt compositions. The average amphibole/silicate melt partition coefficient of Cu [DCu (amph/melt)] is 0.066±0.006, and is essentially constant without showing any correlation with silicate melt composition, dissolved water concentration, temperature or fO2.The low DCu (amph/melt) value suggests that amphibole crystallizing at any stage of calc-alkaline magma evolution is unable to scavenge a significant fraction of the initially available Cu from the melt. However, DCu (amph/melt) is high enough to yield precisely measurable Cu concentrations in natural amphiboles. As DCu (amph/melt) results constant along the liquid line of descent of calc-alkaline magmas, amphibole compositions may thus be used as a proxy to monitor the evolution of the Cu concentration in the silicate melt (not the bulk magma if sulfide is present). This may be useful for understanding the metallogenic evolution of intrusive rocks, in which silicate melt inclusions in minerals are generally absent. As most porphyry-type Cu ore deposits are associated with upper crustal intrusions, in-situ microanalysis of inclusion-free amphiboles in such rocks may help understand ore genesis and might also be used in mineral exploration to assess the fertility of prospective magmatic systems

molecular recognition at interfaces

In order to investigate molecular recognition on surfaces, an azide- functionalized monolayer was deposited on gold. The monolayer was characterized by X-ray photoelectron spectroscopy (XPS) and angle-resolved near-edge X-ray absorption fine structure (NEXAFS) experiments and the decomposition of the azide upon irradiation with X-ray beams was investigated. Subsequently, various alkyne-functionalized host and guest molecules were attached to the azide by 1,3-dipolar cycloaddition. These modified surfaces and their host–guest chemistry were analysed by XPS and angle-resolved NEXAFS. The reversibility of guest binding was shown for one example as a proof of principle

Magnetite solubility and iron transport in magmatic-hydrothermal environments

Abstract-We have examined the effect of pressure on the apparent equilibrium constant, K=, for magnetite solubility (Fe 3 O 4 mt ϩ 6HCl fluid ϩ H 2 fluid ϭ 3FeCl 2 fluid ϩ 4H 2 O fluid ) and the relative iron-carrying capacities of magmatic vapor and brine by conducting experiments in a rhyolite melt-vapor-brine-magnetite system at 800°C, f O 2 ϭ NNO and pressures ranging from 100 to 145 MPa. Iron concentrations in synthetic vapor and brine fluid inclusions were quantified by using laser-ablation inductively-coupled-plasma-mass-spectrometry (LA-ICPMS). Hydrogen chloride (HCl) concentrations in magmatic vapor were inferred by potentiometric measurements of H ϩ in quenched run product fluids. These data yield calculated values for log K=, assuming a H 2 O ϭ X H 2 O , of 1.7, 4.9, 6.2, 6.8 and 9.1 at 100, 110, 130, 140 and 145 MPa, respectively. The concentration of iron in magmatic vapor increases by an order of magnitude, whereas the concentration of iron in magmatic brine remains constant (within 1) with increasing pressure as the 800°C critical pressure is approached along the vapor-brine solvus. The concentrations of iron in vapor and brine fluid inclusions yield calculated partition coefficients (D Fe v/b ) of 0.05, 0.14, 0.27 and 0.56 at 110, 130, 140 and 145 MPa, respectively. Our data reveal that pressure fluctuations may significantly affect the value of log K=. More importantly, the data demonstrate conclusively that a significant amount of iron can be transported by a low-density aqueous vapor in the magmatic-hydrothermal environment

Catch-up-ESUS - follow-up in embolic stroke of undetermined source (ESUS) in a prospective, open-label, observational study: study protocol and initial baseline data

Introduction. So far there is no uniform, commonly accepted diagnostic and therapeutic algorithm for patients with embolic stroke of undetermined source (ESUS). Recent clinical trials on secondary stroke prevention in ESUS did not support the use of oral anticoagulation. As ESUS comprises heterogeneous subgroups including a wide age-range, concomitant patent foramen ovale (PFO), and variable probability for atrial fibrillation (AF), an individualised approach is urgently needed. This prospective registry study aims to provide initial data towards an individual, structured diagnostic and therapeutic approach in ESUS patients. Methods and analysis. The open-label, investigator-initiated, prospective, single-centre, observational registry study (Catch-up-ESUS) started in 01/2018. Consecutive ESUS patients ≥18 years who give informed consent are included and will be followed up for 3 years. Stratified by age <60 or ≥60 years, the patients are processed following a standardised diagnostic and treatment algorithm with an interdisciplinary design involving neurologists and cardiologists. Depending on the strata, patients receive a transesophageal echocardiogram; all patients receive an implantable cardiac monitor. Patients <60 years with PFO and without evidence of concomitant AF are planned for PFO closure within 6 months after stroke. The current diagnostic and therapeutic workup of ESUS patients requires improvement by both standardisation and a more individualised approach. Catch-up-ESUS will provide important data with respect to AF detection and PFO closure and will estimate stratified stroke recurrence rates after ESUS. Ethics and dissemination. The study has been approved by the responsible ethics committee at the Ludwig Maximilian University, Munich, Germany (project number 17–685). Catch-Up-ESUS is conducted in accordance with the Declaration of Helsinki. All patients will have to give written informed consent or, if unable to give consent themselves, their legal guardian will have to provide written informed consent for their participation. The first observation period of the registry study is 1 year, followed by the first publication of the results including follow-up of the patients. Further publications will be considered according the predefined individual follow-up dates of the stroke patients up to 36 months

Effect of starvation and temperature on gonad development of baby clam, Marcia opima (Gmelin)

For studying the influence of feed and temperature on gonad growth and maturity of the baby clam Marcia opima, experiments were conducted for 45 days at temperatures of 23°C and 28°C. The progress of gonadal recovery was followed by periodic determination of gonadosomatic index, condition index, digestive gland index and oocyte diameter. There was significant difference in the gonadosomatic index between fed and unfed clams at 23°C and 28°C. No significant difference in the gonadosomatic index was noted in the fed treatments at 23°C and 28°C, but the time of conditioning had significant influence on the gonadosomatic index. A significant relationship was found between the gonadosomatic index and condition index of the clams in all the treatment

Visualizing metabolic network dynamics through time-series metabolomic data.

BACKGROUND: New technologies have given rise to an abundance of -omics data, particularly metabolomic data. The scale of these data introduces new challenges for the interpretation and extraction of knowledge, requiring the development of innovative computational visualization methodologies. Here, we present GEM-Vis, an original method for the visualization of time-course metabolomic data within the context of metabolic network maps. We demonstrate the utility of the GEM-Vis method by examining previously published data for two cellular systems-the human platelet and erythrocyte under cold storage for use in transfusion medicine. RESULTS: The results comprise two animated videos that allow for new insights into the metabolic state of both cell types. In the case study of the platelet metabolome during storage, the new visualization technique elucidates a nicotinamide accumulation that mirrors that of hypoxanthine and might, therefore, reflect similar pathway usage. This visual analysis provides a possible explanation for why the salvage reactions in purine metabolism exhibit lower activity during the first few days of the storage period. The second case study displays drastic changes in specific erythrocyte metabolite pools at different times during storage at different temperatures. CONCLUSIONS: The new visualization technique GEM-Vis introduced in this article constitutes a well-suitable approach for large-scale network exploration and advances hypothesis generation. This method can be applied to any system with data and a metabolic map to promote visualization and understand physiology at the network level. More broadly, we hope that our approach will provide the blueprints for new visualizations of other longitudinal -omics data types. The supplement includes a comprehensive user\u27s guide and links to a series of tutorial videos that explain how to prepare model and data files, and how to use the software SBMLsimulator in combination with further tools to create similar animations as highlighted in the case studies